The Parts of the Periodic Table Lr Group 4A (or IVA) of the periodic table includes the nonmetal carbon (C), the metalloids silicon (Si) and germanium (Ge), the metals tin (Sn) and lead (Pb), and the yet-unnamed artificially-produced element ununquadium (Uuq). The Group 4A elements have four valence electrons in their highest-energy orbitals (ns2np2). Carbon and silicon can form ionic compounds by gaining four electrons, forming the carbide anion (C4-) and silicide anion (Si4-), but they more frequently form compounds through covalent bonding. Tin and lead can lose either their outermost p electrons to form 2+ charges (Sn2+, the stannous ion, and Pb2+, the plumbous ion) or their outermost s and p electrons to form 4+ charges (Sn4+, the stannic ion, and Pb4+, the plumbic ion). Carbon (C, Z=6). Carbon is most familiar as a black solid is graphite, coal, and charcoal, or as the hard, crystalline diamond form.

The name is derived from the Latin word for charcoal, carbo. It is found in the Earth's crust at a concentration of 480 ppm, making it the 15th most abundant element. It is found in form of calcium carbonate, CaCO3, in minerals such as limestone, marble, and dolomite (a mixture of calcium and magnesium carbonate); calcium carbonate also forms the shells of marine organisms and the coral of coral reefs. Carbon is also found in coal, petroleum, and natural gas. Carbon is one of the most important elements on the periodic table (at least from the perspective of organic chemists!). Pure carbon is found in three stable forms at room temperature: graphite, diamond, and the fullerene form. In graphite, the carbon atoms are connected in sheets, which can slide past each other, which makes graphite able to act as a lubricant, and why it makes marks on paper in the form of pencil "lead." In diamonds, the carbon atoms are held together by covalent bonds in a rigid, three-dimensional framework, which results in a extremely hard and rigid structure.

(Contrary to the James Bond title, diamonds aren't forever, since the graphite form is more stable; however, diamonds turn into graphite at an incredibly slow rate.) Diamonds are so different in their physical characteristics from graphite or charcoal that it was not recognized the diamond was a form of carbons; this was shown by Antoine Lavoisier in 1784 when he demonstrated that both charcoal and diamond could be burned to produce carbon dioxide. Smithson Tennant confirmed this relationship in 1796 when he showed that equal amounts of charcoal and diamond produced equal amounts of carbon dioxide. In the fullerene form, the carbon atoms are arranged in hollow balls, or in hollow tubes (called "nanotubes"); these forms of carbon have very interesting chemical physical properties, and are the subject of intense research by chemists and chemical engineers. Carbon is produced in stars by the triple alpha process, in which three alpha particles are converted into carbon-12.

In this process, two alpha particles (helium nuclei, 42He) fuse to form beryllium-8, which then fuses with another alpha particle to produce carbon-12: 42He + 42He ï¿½ 84Be 84Be + 42He ï¿½ 126C + g This process takes place in older stars where a lot of hydrogen has been converted into helium; the star collapses, raising the pressure and temperature in the core to above 100 million Kelvins, initiating the process of helium burning. Some ionic compounds of carbon are known, but carbon typically forms compounds through covalent bonding. Carbon forms strong, stable covalent bonds to other carbon atoms, and is capable of forming long chains containing anywhere from a few dozen carbon atoms to hundred of thousands of carbon atoms. Carbon can also form bonds to other elements, such as hydrogen, oxygen, nitrogen, sulfur, phosphorus, the halogens, etc. There are therefore a tremendous variety of complex carbon-based chemicals. Organic chemistry is the field of chemistry concerned with the study of carbon-containing compounds.

Such compounds form the basis of life (at least the kinds that we know about). Carbon is found is coal, and petroleum is a very complex mixture of thousands of different hydrocarbons. The burning of carbon and petroleum products (fossil fuels) provides most of the energy which we consume, and contributes to global warming through the release of carbon dioxide into the atmosphere. Carbon is used is the refining of iron and other metals (the oxygen in the ores is carried away in the form of carbon dioxide, leaving behind the elemental metal). Small amounts of carbon are added to iron to make an alloy called steel, which is harder than pure iron. Activated charcoal is a finely powdered form of carbon used to filter out impurities from water or gases. Carbon is taken up by green plants in the form of carbon dioxide, CO2; in the process of photosynthesis, the carbon in the carbon dioxide is transformed into carbohydrates (sugars), lipids, proteins, and all of the other organic molecules which are essential to life. Most carbon is in the form of the carbon-12 isotope (98.90%), which has 6 protons and 6 neutrons in its nucleus.

Carbon-13, which is also non-radioactive, accounts for 1.10% of the world's carbon. Carbon-13 is particularly important in nuclear magnetic resonance spectroscopy (see the section on Hydrogen ); organic molecules contain small amounts of carbon-13, which responds to magnetic fields in a similar fashion as hydrogen-1. Carbon-14, which consists of 6 protons and 8 neutrons, is an unstable isotope produced the reaction of free neutrons (produced from cosmic rays) with nitrogen-14 in the upper atmosphere.

Carbon-14 undergoes beta decay to produce nitrogen-14, with a half-life of 5730 years: 147N + 10n ï¿½ 146C + 11H 146C ï¿½ 147N + 0-1b The amount of carbon-14 thus produced is extremely small — approximately 7 kilograms per year — but small amounts of this carbon-14 are taken up in the form of carbon dioxide along with the "normal" isotopes of carbon by green plants, and this isotope also becomes incorporated into the things that eat the green plants (and also the things that eat the things that eat the green plants — and so on). Once an organism dies, it stops taking in carbon-14 (or anything else, for that matter), and the carbon-14 that it had at the moment of death decays, and is no longer replaced. By measuring the amount of carbon-14 remaining in an organic sample, it is possible to determine how long ago the organism died.

This technique works for carbon-containing materials that are up to about 50,000 years old; beyond that, there is too little carbon-14 remaining to get an accurate date, and some other form of radiometric dating must be used. This technique was developed by Willard F. Libby in the 1950s, who received the Nobel Prize in Chemistry in 1960 for this work. Silicon (Si, Z=14). Silicon is a dark gray element with a metallic luster. The name of the element is derived from the Latin word for flint, silicis. It is found in the Earth's crust at a concentration of 28%, making it the second most abundant element. In the form of silica (SiO2) or one of the silicates (SiO44-), it is found in many different minerals, including clay, quartz, zircon, feldspar, mica, zeolites, aluminosilicates, sand, etc. It is also found in the gemstones opal, agate, rhinestone, and amethyst.

Silicon is one of the most important elements on the periodic table (at least from the perspective of computers!). Ultrapure silicon doped with boron or phosphorus is used as semiconductors in transistors, which are heavily employed in computers, solar panels, and other applications. Silica (which is primarily silicon dioxide, SiO2), is used in the manufacture of glass. Silicones, which consist of chains of alternating silicon and oxygen atoms, are used in oils, lubricants, and silicone rubber. Germanium (Ge, Z=32). Germanium is a hard, grayish white element with a metallic luster. The name of the element is derived from the Latin word for Germany, Germania. It is found in the Earth's crust at a concentration of 2 ppm, making it the 52nd most abundant element. It is found in the ores argyrodite [Ag8GeS6] and germanite [Cu13Fe2Ge2S16], but is more frequently obtained as a by-product of the refining of zinc. Like silicon, germanium is used as a semiconductor, and is widely used in the computer industry.

Silicon and germanium are both metalloids, having some characteristics of both metals and nonmetals. The existence of germanium was predicted by Dimitri Mendeleev in 1869 from a blank space in his periodic table beneath silicon; before it was actually found, the hypothetical element was referred to as "eka-silicon." When germanium was discovered in 1886, its physical and chemical properties matched many of those predicted by Mendeleev. Tin (Sn, Z=50). Tin is a soft, silvery-white metal. The name of the element is derived from the Anglo-Saxon word for the metal, while the chemical symbol "Sn" is derived from the Latin name for the metal, stannum. It is found in the Earth's crust at a concentration of 2 ppm, making it the 49th most abundant element. It is found in the ore cassiterite [tin(IV) oxide, SnO2], and in trace amounts in other minerals.

Elemental tin exists in two allotropic forms: above 13.2 ï¿½C, it is found as white or beta tin, which is the crystalline, metallic form; below 13.2ï¿½C it is found as gray or alpha tin, which has a powdery appearance. Structures made of tin that are cooled below 13.2ï¿½C can start to crumble, a condition known as "tin pest" or "tin disease." This can be prevented by alloying the tin with a small amount of antimony or bismuth. Tin is easily purified in its metallic form from its ores, and has been known since prehistoric times. Tin is commonly plated onto iron, forming a protective surface that prevents the iron from rusting; this is extremely useful in food containers (tin cans) because the tin is nontoxic and is not corrosive. Tin can be hammered into thin sheets ("tin foil"), but this application has been replaced with aluminum foil.

Tin is also used in alloys such as bronze (95% copper and 5% tin), solder (33% tin and 67% lead), pewter (85% tin, 7% copper, 7% antimony, and 4% copper), and dental amalgams (60% silver, 27% tin, and 13% copper). Bronze has been used since at least 3000 BC, since it is harder than copper and more easily made into tools, weapons, works of art, etc. Lead (Pb, Z=82). Lead is a very dense, soft, very malleable, bluish-white or grayish metal. The name of the element is derived from the Anglo-Saxon word for the metal, while the chemical symbol "Pb" is derived from the Latin name for the metal, plumbum. It is found in the Earth's crust at a concentration of 14 ppm, making it the 36th most abundant element.

It is found in the ores galena [lead(II) sulfide, PbS], cerussite [lead(II) carbonate, PbCO3], anglesite [lead(II) sulfate, PbSO4], pyromorphite [Pb5(PO4)3Cl], and boulangerite [Pb5Sb4S11]. Despite its relative rarity, lead has been known since ancient times, since it is comparatively easy to refine and purify. Lead used to be used in plumbing, since lead pipes don't corrode the way that iron pipes do; the Latin name for lead, plumbum, is also the root of the words "plumbing" and "plumber." It is also used in paints, solders, batteries (such as the lead-acid storage batteries found in cars), and radiation shielding. Lead is the end product of the radioactive decay of many heavier elements; the ratio of other elements to lead can be used in radioactive dating of rocks.

Lead used to be used to sweeten wine, through the formation of lead(IV) acetate, Pb(C2H3O2)4, also known as "sugar of lead." Lead was also used as an octane booster for gasoline, in the form of tetraethyl lead, Pb(CH2CH3)4, but this has been phased out due to environmental concerns. The earliest pencils used lead, although now "pencil lead" is graphite mixed with clay. Lead is a cumulative poison; absorption of lead in the body over a long period of time causes it to be stored in the bones in the form of lead phosphate, where it interferes with the production of hemoglobin, leading to anemia, stomach cramps, constipation, headaches, infertility, etc. Ununquadium (Uuq, Z=82). Ununquadium is a synthetic element, produced by the fusion of an isotope of plutonium with an isotope of calcium. "Ununquadium" is a temporary, systematic name (literally meaning "1" "1" "4", the atomic number of the element) until the official name is decided upon.

The longest-lived isotope produced so far, ununquadium-289, has a half-life of 30.4 seconds. It was first produced at the Joint Institute for Nuclear Research (JINR) at Dubna in 1998. Other isotopes have been produced in other labs, with a wide range of half-lives. It has been predicted that an isotope having 114 protons and 184 neutrons, ununquadium-298, should be especially stable, but this isotope has yet to be produced. References John Emsley, The Elements, 3rd edition. Oxford: Clarendon Press, 1998. John Emsley, Nature's Building Blocks: An A-Z Guide to the Elements. Oxford: Oxford University Press, 2001. David L. Heiserman, Exploring Chemical Elements and their Compounds. New York: TAB Books, 1992. Table of Elements in Greek and Latin (Rome) Language. Sidebar Periodic Table of Elements The Greek language and Greek myth have contributed greatly to the sciences, including chemistry. This is most apparent in the Periodic Table of Elements.

A table of the elements with mythological influences, or at least have the Greek language to thank for their names, is below. For kicks, I have included the Latin (Roman) terms also. (Please note: this is not the complete table of elements, only those with Greek or Latin influences.) Actinium From the Greek wordaktinos (ray) Aluminum From the Latin wordalumen, or"bitter". Antimony From the Greek words anti (opposed) and monos (solitude) Argon From the Greek wordargon (inactive) Arsenic From the Greek wordarsenikos and the Latin wordarsenicum, meaning "yellow orpiment". Astatine From the Greek wordastatos (unstable) Barium From the Greek wordbarys (heavy) Bromine From the Greek wordbrômos (stench) Cadmium Symbol: Cd Atomic Number: 48 From the Greek wordkadmeia (ancient name for calamine) and from the Latin word cadmia.Cadmus, in Greek myth, was the founder of Thebes. Calcium From the latin wordcalcis (lime) Carbon Ceres (asteroid), and the Roman version of Demeter, the goddess of agriculture.

Cesium From the Latin wordcaesius (sky blue) Chlorine From the Greek wordkhlôros (green) Chromium From the Greek wordchrôma (color) Copper From the Latin wordcyprium, after the island of Cyprus and birthplace of Aphrodite. Dysprosium From the Greek worddysprositos (hard to get at). Fluorine From the Latin wordfluo (flow) Gold From the Latin wordaurum (gold). In Roman mythology, Aurora was the goddess of dawn--golden indeed. Helium From the Greek wordhêlios (sun); Helios in Greek mythology was the god of the Sun. Hydrogen Symbol: H Atomic Number: 1 From the Greek words hudôr (water) and gennan(generate). Heracles fought the Hydra of Lerna (a sea town) for his second labor. Iodine From the Greek wordiôdes (violet). Iridium Symbol: Ir Atomic Number: 77 From the Latin wordiridis (rainbow). The Greeks had a messenger goddess, Iris, whose colorful cape flowed behind her.

Iron From the Latin wordferrum (iron) Krypton Symbol: Kr Atomic Number: 36 From the Greek wordkryptos (hidden). In modern language, words such as "encrypt" can be discerned from the Greek. Lanthanum From the Greek wordlanthaneis (to lie hidden). Lead Symbol: Pb Atomic Number: 82 Name Origin: From the Greek word protos (first). Some Greeks believd that the first god ever was Protogonus, or "first born". Symbol Origin: From the Latin wordplumbum (lead) Lithium From the Greek wordlithos (stone) Manganese From the Latin wordmangnes (magnet) Molybdenum From the Greek word molubdos (lead) Neodymium Symbol: Nd Atomic Number: 60 From the Greek words neos (new) anddidymos (twin). Twins appear regularly in Greek myth, from the Dioscuri (Castor & Polydeuces) to the divine twins (Artemis & Apollo). Neon Form the Greek word neos (new) Neptunium After the planet Neptune, the Roman sea god, identified as Poseidon in Greek myth.

Niobium Symbol: Nb Atomic Number: 41 After Niobe, daughter of mythical king (Tantalus). She had bragged about her set of seven girls and seven boys, scoffing at Leto for only having two children. Apollo and Artemis promptly killed her offspring. Niobe, in despair, was turned to stone by the gods. Osmium From the Greek word osmë (odor) Oxygen From the Greek words oxus (acid) andgennan (generate) Palladium From the Greek goddess (Pallas) and after an asteroid Phosphorous Symbol: P Atomic Number: 15 From the Greek words phôs (light) andphoros (bearer), Phosphoros was a god of light in Greek myth. Plutonium After the planet Pluto and the Latin god of the Underworld (Hades in Greek). Potassium Symbol Origin: From the Latin word kalium Praseodymium From the Greek words prasios (green) anddidymos (twin) Promethium From the Titan Prometheus who stole fire of the sky and gave it to man. Protactinium From the Greek word protos (first) [see name origin for lead].

Radium From the Latin word radius (ray) Rhodium From the Greek word rhodon (rose) Rubidium From the Latin word rubidus (red) Ruthenium From the Latin word Ruthenia (Russia) Selenium From the Greek word Selênê, known as the goddess of the moon. Sodium Symbol Origin: From the Latin wordnatrium (sodium) Silicon From the Latin word silex (flint) Sulfur From the Latin word sulfur (brimstone) Tantalum Symbol: Ta Atomic Number: 73 After king Tantalus, a son of Zeus who earned the disfavor of the gods for attempting to serve his son Pelops as a meal. He was condemned to the Underworld with eternal thirst and hunger though a river and fruit tree were just beyond his grasp. Technetium From the Greek word technêtos (artificial) Tellurium From the Greek word tellus (Earth) Thallium From the Greek word thallos (young shoot) Tin Symbol Origin: From the Latin wordstannum (tin) Titanium From the Greek word titanos (Titans). The Titans were the "original" gods before the Olympians.

Uranium Symbol: U Atomic Number: 92 After the planet Uranus, the original sky god who was the son and spouse of Gaia, or Mother Earth. Xenon Named by Davy in 1808 History & Etymology Silica (silicon dioxide, SiO2) is widely and most abundantly distributed in nature, both in the free state and in combination with metallic oxides. Free silica constitutes the greater part of sand and sandy rocks; when fairly pure it occurs in the large crystals which we know as quartz, and which, when coloured, form the gem-stones amethyst, cairngorm, cat's-eye and jasper. Amorphous forms also occur: chalcedony, and its coloured modifications agate, carnelian, onyx and sard, together with opal are examples. Sir Humphry Davy in 1800 thought silica to be a compound and not an element. In 1808, he did experiments for the decomposition of alumine, silex, zircone, and glucine.

He failed to isolate the metals in these, as he reported in his paper for the Royal Society of London on 30 June 1808, but he suggested names for the metals (note) : Cf. Aluminium , Zirconium , and Beryllium ("Glucium") Later in 1811, Louis-Joseph Gay-Lussac (1778-1850) and Louis-Jacques Thénard (1777-1857) probably prepared impure amorphous Silicon by heating potassium with silicon tetrafluoride. Jakob Berzelius (1779-1848), generally credited with the discovery, in 1824 succeeded in preparing amorphous Silicon by the same general method as used earlier, but he purified the product by removing the fluosilicates by repeated washings. The name Silicium is derived from silica > Latin silex for flint (SiO2), a hard stone. The Latin name silicium was adopted to conform with the -ium ending of most elements. The suffix -on in English was added because of its resemblance to Carbon.

Alternative names SILICON, the chief substance in Glass and Pots, Call'd Silicium, is a brown metalloid. Silicon exists in three diff'rent forms: Amorphous; in crystalslike the Diamond; And scaleslike Graphite: the two later kinds scratch glass. Silicon Amorphous has no lustre, Heated in Air it burns till cover'd with Oxide. (...) Silica (the Dioxide) occurs largely In flints, and the rocks forming the Earth's crust; 'Tis most abundant in the primary Rocks; It will not vapour at any known heat. The colourless, transparent Rock Crystal Is nearly pure Silica. Agate, Quartz, Flint, and Chalcedony, are chiefly Silica; Silicon is never found in native state, But combined with metals, or as Silica. J. Carrington Sellars, Chemistianity, 1873 , p. 68-70 Further reading Mary Elvira Weeks, Discovery of the Elements, comp. rev. by Henry M. Leicester (Easton, Pa.: Journal of Chemical Education, 1968), pp. 555-557.

James B. Calvert, "Silicon" 2002 (on-line) . On Winterl and his ideas: Kleinert, Andreas. "Volta,the German Controversy on Physics and Naturphilosophie and his Relations with Johann Wilhelm Ritter". In: Fabio Bevilacqua and Lucio Fregonese, Nuova Voltiana: Studies on Volta and his time, vol. 4.. Pavia: Università degli Studi di Pavia, 2002 (PDF on-line) . Chemistry of Silicon - Chemistry LibreTexts Chemistry of Silicon Contributors Silicon, the second most abundant element on earth, is an essential part of the mineral world. It's stable tetrahedral configuration makes it incredibly versatile and is used in various way in our every day lives. Found in everything from spaceships to synthetic body parts, silicon can be found all around us, and sometimes even in us. Introduction The name for silicon is taken from the Latin silex which means "flint". The element is second only to oxygen in abundance in the earth's crust and was discovered by Berzelius in 1824.

The most common compound of silicon, \(SiO_2\), is the most abundant chemical compound in the earth's crust, which we know it better as common beach sand. Properties Silicon is a crystalline semi-metal or metalloid. One of its forms is shiny, grey and very brittle (it will shatter when struck with a hammer). It is a group 14 element in the same periodic group as carbon, but chemically behaves distinctly from all of its group counterparts. Silicon shares the bonding versatility of carbon, with its four valence electrons, but is otherwise a relatively inert element. However, under special conditions, silicon be made to be a good deal more reactive. Silicon exhibits metalloid properties, is able to expand its valence shell, and is able to be transformed into a semiconductor; distinguishing it from its periodic group members. Table 1: Properties of Silicon Symbol 28Si 29Si 30Si Where Silicon is Found 27.6% of the Earth's crust is made up of silicon. Although it is so abundant, it is not usually found in its pure state, but rather its dioxide and hydrates.

\(SiO_2\) is silicon's only stable oxide , and is found in many crystalline varieties. Its purest form being quartz, but also as jasper and opal. Silicon can also be found in feldspar, micas, olivines, pyroxenes and even in water (Figure 1). In another allotropic form silicon is a brown amorphous powder most familiar in "dirty" beach sand. The crystalline form of silicon is the foundation of the semiconductor age. Figure 1: Sand is an easy to find silicon deposit Silicates Silicon is most commonly found in silicate compounds. Silica is the one stable oxide of silicon, and has the empirical formula SiO2. Silica is not a silicon atom with two double bonds to two oxygen atoms. Silica is composed of one silicon atom with four single bonds to four oxygen molecules (Figure 2). Figure 2: The net charge of silica is minus 4 Silica, i.e. silicon dioxide, takes on this molecular form, instead of carbon dioxide's characteristic shape, because silicon's 3p orbitals make it more energetically favorable to create four single bonds with each oxygen rather than make two double bonds with each oxygen atom.

This leads to silicates linking together in -Si-O-Si-O- networks called silicates. The empirical form of silica is SiO2 because, with respect to the net average of the silicate, each silicon atom has two oxygen atoms. Figure 3: This is a representation of the tetrahedral silica complex The tetrahedral SiO44- complex (see Figure 3), the core unit of silicates, can bind together in a variety of ways, creating a wide array of minerals. Silicon is an integral component in minerals, just as Carbon is an essential component of organic compounds. Neosilicates In nesosilicates the silicate tetrahedral does not share any oxygen molecules with other silicate tetrahedrals, and instead balances out its charge with other metals. The core structure of neosilicate is simply a lone tetrahedral silica unit (Figure 4). The empirical formula for the core structure of a neosilicate is SiO44-. Figure 4: The core of a neosilicate Neosilicates make up the outer fringes of a group of minerals known as olivines.

Sorosilicates In sorosilicates two silicate tetrahedrals join together by sharing an oxygen atom at one of their corners. The core structure of a sorosilicate is a pair of silica tetrahedra. (see Figure 5) Figure 5: The core of a sorosilicate The mineral thortveitie is an example of a sorosilicate complex. Cyclosilicates In cyclosilicates three or more silica tetrahedrals share two corners of an oxygen atom. The core structure of a cyclosilicate is a closed ring of silica tetrahedra. (see Figure 6) Figure 6: The core of a cyclosilicate The mineral beryl is an example of a cyclosilicate complex. Inosilicates Inosilicates are complexes where each tetrahedral share two corners with another silica tetrahedral to create a single chain (see Figure 7) or three corners to create a double chain (Figure 8). The core structure of an inosilicate is either an infinite single or double chain of silca tetrahedrals.

Figure 7: The core of a single chain inosilicate The mineral group pyroxenes are examples of single chain inosilicates. The core of a double chain inosilicate Figure 8 The mineral amphibole is an example of a double chain inosilicate. Phyllosilicates Phyllosilicates are silica complexes where each tetradedral shares three corners and creates a sheet of silicon and oxygen. (see Figure 9) The core complex of a phyllosilicate is an infinite sheet of connected silica tetrahedrals. The mineral talc is an example of a phyllosilicate complex. Tectosilicates Tectosilicates are three dimensional silicate structures. The core structure of a tectosilicate is an infinite network of connected silica tetrahedrals. (see Figure 10) The 3d core of tectosilicate Figure 10 The mineral quartz is an example of a tectosilicate complex. Although many silica complexes form network covalent solids , quartz is a particularly good example of a network solid.

Silicates in general share the properties of covalent solids, and this affiliated array of properties makes them very useful in modern day industry. Silanes Silanes are silicon-hydrogen compounds. Carbon-hydrogen compounds form the backbone of the living world with seemingly endless chains of hydrocarbons . With the same valence configuration, and thus the same chemical versatility, silicon could conceivably play a role of similar organic importance. But silicon does not play an integral role in our day to day biology. One principal reasons underlies this. Like hydrocarbons, silanes progressively grow in size as additional silicon atoms are added. But there is a very quick end to this trend. The largest silane has a maximum of six silicon atoms. (see Figure 11) The largest silane, hexasilane Figure 11 Hexasilane is the largest possible silane because Si-Si bonds are not particularly strong. In fact, silanes are rather prone to decomposition. Silanes are particularly prone to decomposition via oxygen. Silanes also have a tendency to swap out there hydrogens for other elements and become organosilanes.

(see Figure 12) The organosilane, dichlorodimethylsilane Figure 12 Silanes have a variety of industrial and medical uses. Among other things, silanes are used as water repellents and sealants. Silicones Silicones are a synthetic silicon compound, they are not found in nature. When specific silanes are made to undergo a specific reaction, they are turned into silicone, a very special silicon complex. Silicone is a polymer and is prized for its versatility, temperature durability, low volatility, general chemical resistance and thermal stability. Silicone has a unique chemical structure, but it shares some core structural elements with both silicates and silanes. (See Figure 13) The core unit of a silicone Figure 13 Silicone polymers are used for a huge array of things. Among numerous other things, breast implants are made out of silicone. Silicon Halides Silicon has a tendency to readily react with halogens . The general formula depicting this is SiX4, where X represents any halogen. Silicon can also expand its valence shell, and the laboratory preparation of [SiF6]2- is a definitive example of this.

However, it is unlikely that silicon could create such a complex with any other halogen than fluorine, because six of the larger halogen ions cannot physically fit around the central silicon atom. Silicon halides are synthesized to purify silicon complexes. Silicon halides can easily be made to give up their silicon via specific chemical reactions that result in the formation of pure silicon. Applications Silicon is a vital component of modern day industry. Its abundance makes it all the more useful. Silicon can be found in products ranging from concrete to computer chips. Electronics The high tech sectors adoption of the title Silicon Valley underscores the importance of silicon in modern day technology. Pure silicon, that is essentially pure silicon, has the unique ability of being able to discretely control the number and charge of the current that passes through it. This makes silicon play a role of utmost importance in devices such as transistors, solar cells, integrated circuits, microprocessors, and semiconductor devices, where such current control is a necessity for proper performance. Semiconductors exemplify silicon's use in contemporary technology. Semiconductors Semiconductors are unique materials that have neither the electrical conductivity of a conductor nor of an insulator.

Semiconductors lie somewhere in between these two classes giving them a very useful property. Semiconductors are able to manipulate electric current. They are used to rectify, amplify, and switch electrical signals and are thus integral components of modern day electronics. Semiconductors can be made out of a variety of materials, but the majority of semiconductors are made out of silicon. But semiconductors are not made out of silicates, or silanes, or silicones, they are made out pure silicon, that is essentially pure silicon crystal. Like carbon, silicon can make a diamond like crystal. This structure is called a silicon lattice . (see Figure 15) Silicon is perfect for making this lattice structure because its four valence electrons allow it too perfectly bond to four of its silicon neighbors. an example of a silicon latice Figure 15 However, this silicon lattice is essentially an insulator, as there are no free electrons for any charge movement, and is therefore not a semiconductor. This crystalline structure is turned into a semiconductor when it is doped. Doping refers to a process by which impurities are introduced into ultra pure silicon, thereby changing its electrical properties and turning it into a semiconductor.

Doping turns pure silicon into a semiconductor by adding or removing a very very small amount of electrons, thereby making it neither an insulator nor a conductor, but a semiconductor with limited charge conduction. Subtle manipulation of pure silicon lattices via doping generates the wide variety of semiconductors that modern day electrical technology requires. Semiconductors are made out of silicon for two fundamental reasons. Silicon has the properties needed to make semiconductors, and silicon is the second most abundant element on earth. Glasses Glass is another silicon derivate that is widely utilized by modern day society. If sand, a silica deposit, is mixed with sodium and calcium carbonate at temperatures near 1500 degrees Celsius, when the resulting product cools, glass forms. Glass is a particularly interesting state of silicon. Glass is unique because it represents a solid non-crystalline form of silicon. The tetrahedral silica elements bind together, but in no fundamental pattern behind the bonding. (see Figure 16) Non-crystalline silica Figure 16 The end result of this unique chemical structure is the often brittle typically optically transparent material known as glass. This silica complex can be found virtually anywhere human civilization is found.

Glass can be tainted by adding chemical impurities to the basal silica structure. (see Figure 17) The addition of even a little Fe2O3 to pure silica glass gives the resultant mixed glass a distinctive green color. Non-crystalline silica with unknown impurities Figure 17 Fiber Optics Modern fiber optic cables must relay data via undistorted light signals over vast distances. To undertake this task, fiber optic cables must be made of special ultra-high purity glass. The secret behind this ultra-high purity glass is ultra pure silica. To make fiber optic cables meet operational standards, the impurity levels in the silica of these fiber optic cables has been reduced to parts per billion. This level of purity allows for the vast communications network that our society has come to take for granted. Ceramics Silicon plays an integral role in the construction industry. Silicon, specifically silica, is a primary ingredient in building components such as bricks, cement, ceramics, and tiles. Additionally, silicates, especially quartz, are very thermodynamically stable. This translates to silicon ceramics having high heat tolerance. This property makes silicon ceramics particularily useful from things ranging from space ship hulls to engine components.

(see Figure 18) Silica ceramics on the underside of the orbital are used for rentry Figure 18 Polymers Silicone polymers represent another facet of silicon's usefulness. Silicone polymers are generally characterized by their flexibility, resistance to chemical attack, impermeability to water, and their ability to retain their properties at both high and low temperatures. This array of properties makes silicone polymers very useful. Silicone polymers are used in insulation, cookware, high temperature lubricants, medical equipment, sealants, adhesives, and even as an alternative to plastic in toys. Production As silicon is not normally found in its pure state, silicon must be chemically extracted from its naturally occurring compounds. Silica is the most prevalent form of naturally occurring silicon. Silica is a strongly bonded compound and it requires a good deal of energy to extract the silicon out of the silica complex. The principal means of this extraction is via a chemical reaction at a very high temperature. The synthesis of silicon is fundamentally a two step process. First, use a powerful furnace to heat up the silica to temperatures over 1900 degrees celsius, and second, add carbon.

At temperatures over 1900 degrees celsius, carbon will reduce the silica compound to pure silicon. Purification For some silicon applications, the purity of freshly produced silicon is not satisfactory. To meet the demand for high purity silicon, techniques have been devised to further refine the purity of extracted silicon. Purification of silicon essentially involves taking synthesized silicon, turning it into a silicon compound that can be easily distilled, and then breaking up this new formed silicon compound to yield an ultra pure silicon product. There are several distinct purification methods available, but most chemical forms of purification involve both silane and silicon halide complexes. Trivia Silicon is the eighth most abundant element in the universe. Silicon was first identified in 1787 but first discovered as an element 1824. Silicon is an important element in the metabolism of plants, but not very important in the metabolism of animals. Silicon is harmless to ingest and inject into the body but it is harmful to inhale. Silicosis is the name of the disease associated with inhaling too much of the silicon compound silica. It primarily afflicts construction workers. Silica is a major chemical component of asbestos. Outside links Krasnoshchekov, V.V.

and LV Myshlyaeva. Analtical Chemistry of Silicon. New York: Halsted Press, 1974. p 1-6. Rochow, Eugene G. Silicon and Silicones. New York: Springer-Verlag, 1987. preface and p 1-30 Campion, Gillis, and Oxtoby. "Principles of Modern Chemistry." 6th Ed. Belmont, CA: Thomson Brooks/Cole. Petrucci, Ralph H., Harwood, William S., Herring, F. G., and Madura Jeffrey D. "General Chemistry: Principles & Modern Applications." 9th Ed. New Jersey: Pearson Education, Inc., 2007. Problems Highlight area next to "Ans" to see answer How many oxides does Silicon have, and what are they? Ans: 1 oxide O2 How does a silicate tetrahedral balance its charge if not bonded with another silicate? Ans: By bonding to positively charged metals. Carbon is to organic compounds as silica is to: Ans: minerals How big is the largest silicon-hydrogen compound?

Ans: The largest silane is hexasilane, with six silicon atoms and fourteen hydrogens. Why is silicon important to computers? Ans: It is used to make semiconductors. Contributors

Question: Which chemical element's name is taken from the Latin for flint?
Answer: Silicon